Hair conditioner compositions which provide conditioning to the hair are well known in the art. Such compositions comprise one or more conditioning agents. The purpose of the conditioning agent is to make the hair easier to comb when wet and more manageable when dry, e.g. less static and fly-away. They also make the hair feel softer. Typically, these conditioning agents are either water-insoluble oily materials which act by spreading on the hair in the form of a film, or cationic surfactant materials or polymers, which adsorb onto the hair surface.
Hair conditioners can be in the form of rinse-off conditioners (usually applied to the hair after shampooing as a liquid or mousse) or leave-on products such as hair oils or serums, mousses and styling products.
Typically, water-insoluble oily conditioning materials are dispersed in aqueous products in the form of small droplets or particles in order to facilitate the stability of the dispersion to phase separation and to enhance the deposition of the oily material onto the hair.
A preferred water-insoluble oily conditioning material is based on silicone polymers, preferably polydimethylsiloxanes, with or without various functionalising groups. Non-silicone conditioning oils include hydrocarbon oils and triglycerides.
Although these cationic surfactants, cationic polymers and water-insoluble oily conditioning materials provide conditioning effects to the hair, it is desirable to improve the conditioning effects obtainable from them.
Natural oils secreted by the sebaceous gland at the base of the hair lead to hair being more hydrophobic near the root rather than near the tip. This means that droplets of hydrophobic conditioning oil deposited onto hair are more likely to spread and form films on the hair at the base of the hair rather than near the tip of the hair, and this is found in practice.
Certain consumers find the effects arising from this effect to be undesirable in that it may lead to the hair feeling greasy at the roots or heavy and dull.
In attempts to overcome the problems in the prior art, it has been considered desirable to target the deposition of the conditioning oil droplets onto the tip regions of the hair in preference to the basal regions, and much research has been carried out in this field of work. Although it would be desirable to make the surface of the oil droplets more hydrophilic, it had always been considered that the high levels of cationic surfactant in rinse-off hair conditioner compositions would dominate the surface chemistry and hydrophilicity of the oil droplets. Thus the conventional view is that irrespective of any additives added to the conditioning oil droplets, the conditioning surfactant would control the droplet hydrophilicity and deposition.
It has now surprisingly been found, that by blending certain types of surface active block copolymers of a high molecular weight with conditioning oil emulsion droplets, enhanced deposition of the droplets onto the tip regions of hairs can be achieved. Although not wishing to be bound by the scientific reasoning underlying this phenomenon, it seems that surface active polymer remains at the droplet surface, even in the presence of other surfactant molecules from the conditioner, making the droplets more hydrophilic than the droplets in conventional oil droplet-containing hair conditioner compositions. This leads to improved deposition of the droplets towards the more hydrophilic tip region of the hair.
The present invention concerns the use of Poloxamers (CTFA designation) to enhance the deposition of hydrophobic conditioning oil onto the hair tip region from hair conditioner compositions, particularly from rinse-off conditioner compositions.
U.S. Pat. No. 3,753,916 discloses the use of cationic polymers as deposition aids for conditioning oils. Poloxamers are mentioned under the trade name Pluronic as optional ingredients.
WO 92/14440 discloses Pluronics (Poloxamers) in anti-dandruff shampoos as one of a class of ‘synergisers’ that unexpectedly enhance anti-dandruff efficacy.
WO 96/17590 discloses personal washing compositions containing lipids as the conditioning phase. The lipids are emulsified with a nonionic emulsifier. Poloxamers are listed as one of the possible polyalkoxy nonionic emulsifiers with HLB (hydrophile lipophile balance) in the range 1 to 15.
U.S. Pat. No. 5,100,657 lists Pluronics (Poloxamers) as optional ingredients in hair conditioner compositions.